The parliamentary system of government would facilitate Armenia’s democratization and put its leaders in a better position to resist pressures from Russia, Alexander Arzumanian, a prominent opposition politician, said on Tuesday.

Arzumanian was among opposition deputies who voted on Monday to endorse President Serzh Sarkisian’s package of constitutional changes envisaging the country’s transformation into a parliamentary republic.

About a dozen other opposition lawmakers remained adamant in rejecting the proposed changes and insisting that they are aimed at enabling Sarkisian to officially or unofficially stay in power after his second presidential term expires in 2018.

Arzumanian disagreed with their arguments, saying that Sarkisian can use the existing Armenian constitution to prolong his rule by becoming prime minister. He argued that the the parliament and the government already have significant powers vis-à-vis the president of the republic.

“I don’t care about Serzh Sarkisian’s [political] fate,” he told RFE/RL’s Armenian service (Azatutyun.am). “If he wants to stay on, he can use the existing constitution to rig the parliamentary elections, win a parliamentary majority and become prime minister.”

Arzumanian, who had served as Armenia’s foreign minister in 1996-1998, insisted that the parliamentary republic would decentralize power in the country, something which he said is essential for democratic change. This is why, he said, the Armenian Pan-National Movement (HHSh), a pro-Western opposition party of which he is a leading member, called for such a transition in its most recent platform adopted two years ago.

Arzumanian also claimed that Russia would find it harder to impose decisions on an Armenian prime minister subordinate to the parliament, rather than the president, within the framework of the Eurasian Economic Union (EEU). “The prime minister would have to come back to Armenia [from EEU summits,] consult with the National Assembly and hold an open discussion before agreeing to anything,” he said.

Not all leaders of the HHSh have agreed with this line of reasoning. One of them, Karapet Rubinian, left the party in late August after Arzumanian and several other HHSh leaders met with Sarkisian to discuss his constitutional changes. Rubinian said that they had no moral right to talk to a man who “usurped power through murders and mass repressions.”

The HHSh claims to be the legal successor to an eponymous party that led Armenia to independence in 1991-1992. It is headed by veteran politicians who used to be close associates of former President Levon Ter-Petrosian. They fell out with Ter-Petrosian in 2010-2012.

Ter-Petrosian’s Armenian National Congress (HAK) is one of the opposition groups categorically rejecting Sarkisian’s constitutional changes. The HAK and another opposition party represented in the parliament, Zharangutyun, have teamed up with over two dozen smaller groups to try to scuttle their passage in a referendum expected later this year. They plan to hold rallies across Armenia in the run-up to the vote.

Arzumanian, who played a major role in Ter-Petrosian’s failed 2008 bid to return to power, was skeptical about the success of their No campaign. “If they show me that they are capable of effecting regime change, I will immediately join them on the street,” he said. “They risk once again disappointing the people.”